The ion funnel has become a well-established interface for enabling the manipulation and focusing of ions between an ion source at the entrance of the ion funnel and an ion mobility or other ion manipulation device at the exit of the ion funnel. Current ion funnel interfaces, which have circular ring electrodes with a focusing lens at the exit, as depicted in FIG. 1, provide only limited ion transmission due to unmatched fields between the ion funnel and the ion manipulation devices, of noncircular entrance, at the exit of the ion funnel. This constitutes a geometric and field mismatch that results in ion loss at the ion funnel-ion mobility device interface.
What is needed is an ion funnel device that provides better sensitivity, higher-efficiency ion transfer, and stable performance for an extensive period of time.